Merge pull request 99designs#235 from vektah/generate-resolver-on-init

Generate resolver on init

cmd/init.go

@@ -61,11 +61,32 @@ var initCmd = &cobra.Command{
 	Long:  "",
 	Run: func(cmd *cobra.Command, args []string) {
 		initSchema()
-		initConfig()
+		config := initConfig()
+
+		generateGraph(config)
 	},
 }
 
-func initConfig() {
+func generateGraph(config *codegen.Config) {
+	schemaRaw, err := ioutil.ReadFile(config.SchemaFilename)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "unable to open schema: "+err.Error())
+		os.Exit(1)
+	}
+	config.SchemaStr = string(schemaRaw)
+
+	if err = config.Check(); err != nil {
+		fmt.Fprintln(os.Stderr, "invalid config format: "+err.Error())
+		os.Exit(1)
+	}
+
+	if err := codegen.Generate(*config); err != nil {
+		fmt.Fprintln(os.Stderr, err.Error())
+		os.Exit(1)
+	}
+}
+
+func initConfig() *codegen.Config {
 	var config *codegen.Config
 	var err error
 	if configFilename != "" {
@@ -84,6 +105,10 @@ func initConfig() {
 				configFilename = ".gqlgen.yml"
 			}
 			config = codegen.DefaultConfig()
+			config.Resolver = codegen.PackageConfig{
+				Filename: "resolver.go",
+				Type:     "Resolver",
+			}
 		} else if config != nil {
 			fmt.Fprintln(os.Stderr, "config file is already exists")
 			os.Exit(0)
@@ -130,6 +155,8 @@ func initConfig() {
 		fmt.Fprintln(os.Stderr, "unable to write config file: "+err.Error())
 		os.Exit(1)
 	}
+
+	return config
 }
 
 func initSchema() {

codegen/build.go

@@ -31,19 +31,28 @@ type ModelBuild struct {
 	Enums       []Enum
 }
 
+type ResolverBuild struct {
+	PackageName   string
+	Imports       []*Import
+	ResolverType  string
+	Objects       Objects
+	ResolverFound bool
+}
+
 // Create a list of models that need to be generated
 func (cfg *Config) models() (*ModelBuild, error) {
 	namedTypes := cfg.buildNamedTypes()
 
-	prog, err := cfg.loadProgram(namedTypes, true)
+	progLoader := newLoader(namedTypes, true)
+	prog, err := progLoader.Load()
 	if err != nil {
 		return nil, errors.Wrap(err, "loading failed")
 	}
 	imports := buildImports(namedTypes, cfg.Model.Dir())
 
 	cfg.bindTypes(imports, namedTypes, cfg.Model.Dir(), prog)
 
-	models, err := cfg.buildModels(namedTypes, prog)
+	models, err := cfg.buildModels(namedTypes, prog, imports)
 	if err != nil {
 		return nil, err
 	}
@@ -55,11 +64,47 @@ func (cfg *Config) models() (*ModelBuild, error) {
 	}, nil
 }
 
+// bind a schema together with some code to generate a Build
+func (cfg *Config) resolver() (*ResolverBuild, error) {
+	progLoader := newLoader(cfg.buildNamedTypes(), true)
+	progLoader.Import(cfg.Resolver.ImportPath())
+
+	prog, err := progLoader.Load()
+	if err != nil {
+		return nil, err
+	}
+
+	destDir := cfg.Resolver.Dir()
+
+	namedTypes := cfg.buildNamedTypes()
+	imports := buildImports(namedTypes, destDir)
+	imports.add(cfg.Exec.ImportPath())
+
+	cfg.bindTypes(imports, namedTypes, destDir, prog)
+
+	objects, err := cfg.buildObjects(namedTypes, prog, imports)
+	if err != nil {
+		return nil, err
+	}
+
+	def, _ := findGoType(prog, cfg.Resolver.ImportPath(), cfg.Resolver.Type)
+	resolverFound := def != nil
+
+	return &ResolverBuild{
+		PackageName:   cfg.Resolver.Package,
+		Imports:       imports.finalize(),
+		Objects:       objects,
+		ResolverType:  cfg.Resolver.Type,
+		ResolverFound: resolverFound,
+	}, nil
+}
+
 // bind a schema together with some code to generate a Build
 func (cfg *Config) bind() (*Build, error) {
 	namedTypes := cfg.buildNamedTypes()
 
-	prog, err := cfg.loadProgram(namedTypes, true)
+	progLoader := newLoader(namedTypes, true)
+	prog, err := progLoader.Load()
 	if err != nil {
 		return nil, errors.Wrap(err, "loading failed")
 	}
@@ -105,13 +150,12 @@ func (cfg *Config) bind() (*Build, error) {
 }
 
 func (cfg *Config) validate() error {
-	namedTypes := cfg.buildNamedTypes()
-
-	_, err := cfg.loadProgram(namedTypes, false)
+	progLoader := newLoader(cfg.buildNamedTypes(), false)
+	_, err := progLoader.Load()
 	return err
 }
 
-func (cfg *Config) loadProgram(namedTypes NamedTypes, allowErrors bool) (*loader.Program, error) {
+func newLoader(namedTypes NamedTypes, allowErrors bool) loader.Config {
 	conf := loader.Config{}
 	if allowErrors {
 		conf = loader.Config{
@@ -130,8 +174,7 @@ func (cfg *Config) loadProgram(namedTypes NamedTypes, allowErrors bool) (*loader
 			conf.Import(imp.Package)
 		}
 	}
-
-	return conf.Load()
+	return conf
 }
 
 func resolvePkg(pkgName string) (string, error) {

codegen/codegen.go

@@ -1,9 +1,7 @@
 package codegen
 
 import (
-	"bytes"
-	"fmt"
-	"io/ioutil"
+	"log"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -14,7 +12,6 @@ import (
 	"github.com/vektah/gqlparser"
 	"github.com/vektah/gqlparser/ast"
 	"github.com/vektah/gqlparser/gqlerror"
-	"golang.org/x/tools/imports"
 )
 
 func Generate(cfg Config) error {
@@ -30,15 +27,10 @@ func Generate(cfg Config) error {
 		return errors.Wrap(err, "model plan failed")
 	}
 	if len(modelsBuild.Models) > 0 || len(modelsBuild.Enums) > 0 {
-		var buf *bytes.Buffer
-		buf, err = templates.Run("models.gotpl", modelsBuild)
-		if err != nil {
-			return errors.Wrap(err, "model generation failed")
-		}
-
-		if err = write(cfg.Model.Filename, buf.Bytes()); err != nil {
+		if err = templates.RenderToFile("models.gotpl", cfg.Model.Filename, modelsBuild); err != nil {
 			return err
 		}
+
 		for _, model := range modelsBuild.Models {
 			modelCfg := cfg.Models[model.GQLType]
 			modelCfg.Model = cfg.Model.ImportPath() + "." + model.GoType
@@ -57,23 +49,46 @@ func Generate(cfg Config) error {
 		return errors.Wrap(err, "exec plan failed")
 	}
 
-	var buf *bytes.Buffer
-	buf, err = templates.Run("generated.gotpl", build)
-	if err != nil {
-		return errors.Wrap(err, "exec codegen failed")
+	if err := templates.RenderToFile("generated.gotpl", cfg.Exec.Filename, build); err != nil {
+		return err
 	}
 
-	if err = write(cfg.Exec.Filename, buf.Bytes()); err != nil {
-		return err
+	if cfg.Resolver.IsDefined() {
+		if err := generateResolver(cfg); err != nil {
+			return errors.Wrap(err, "generating resolver failed")
+		}
 	}
 
-	if err = cfg.validate(); err != nil {
+	if err := cfg.validate(); err != nil {
 		return errors.Wrap(err, "validation failed")
 	}
 
 	return nil
 }
 
+func generateResolver(cfg Config) error {
+	resolverBuild, err := cfg.resolver()
+	if err != nil {
+		return errors.Wrap(err, "resolver build failed")
+	}
+	filename := cfg.Resolver.Filename
+
+	if resolverBuild.ResolverFound {
+		log.Printf("Skipped resolver: %s.%s already exists\n", cfg.Resolver.ImportPath(), cfg.Resolver.Type)
+		return nil
+	}
+
+	if _, err := os.Stat(filename); os.IsNotExist(errors.Cause(err)) {
+		if err := templates.RenderToFile("resolver.gotpl", filename, resolverBuild); err != nil {
+			return err
+		}
+	} else {
+		log.Printf("Skipped resolver: %s already exists\n", filename)
+	}
+
+	return nil
+}
+
 func (cfg *Config) normalize() error {
 	if err := cfg.Model.normalize(); err != nil {
 		return errors.Wrap(err, "model")
@@ -83,6 +98,12 @@ func (cfg *Config) normalize() error {
 		return errors.Wrap(err, "exec")
 	}
 
+	if cfg.Resolver.IsDefined() {
+		if err := cfg.Resolver.normalize(); err != nil {
+			return errors.Wrap(err, "resolver")
+		}
+	}
+
 	builtins := TypeMap{
 		"__Directive":  {Model: "github.com/vektah/gqlgen/graphql/introspection.Directive"},
 		"__Type":       {Model: "github.com/vektah/gqlgen/graphql/introspection.Type"},
@@ -129,31 +150,3 @@ func abs(path string) string {
 	}
 	return filepath.ToSlash(absPath)
 }
-
-func gofmt(filename string, b []byte) ([]byte, error) {
-	out, err := imports.Process(filename, b, nil)
-	if err != nil {
-		return b, errors.Wrap(err, "unable to gofmt")
-	}
-	return out, nil
-}
-
-func write(filename string, b []byte) error {
-	err := os.MkdirAll(filepath.Dir(filename), 0755)
-	if err != nil {
-		return errors.Wrap(err, "failed to create directory")
-	}
-
-	formatted, err := gofmt(filename, b)
-	if err != nil {
-		fmt.Fprintf(os.Stderr, "gofmt failed: %s\n", err.Error())
-		formatted = b
-	}
-
-	err = ioutil.WriteFile(filename, formatted, 0644)
-	if err != nil {
-		return errors.Wrapf(err, "failed to write %s", filename)
-	}
-
-	return nil
-}

codegen/config.go

@@ -60,6 +60,7 @@ type Config struct {
 	SchemaStr      string        `yaml:"-"`
 	Exec           PackageConfig `yaml:"exec"`
 	Model          PackageConfig `yaml:"model"`
+	Resolver       PackageConfig `yaml:"resolver,omitempty"`
 	Models         TypeMap       `yaml:"models,omitempty"`
 
 	schema *ast.Schema `yaml:"-"`
@@ -68,6 +69,7 @@ type Config struct {
 type PackageConfig struct {
 	Filename string `yaml:"filename,omitempty"`
 	Package  string `yaml:"package,omitempty"`
+	Type     string `yaml:"type,omitempty"`
 }
 
 type TypeMapEntry struct {
@@ -128,6 +130,10 @@ func (c *PackageConfig) Check() error {
 	return nil
 }
 
+func (c *PackageConfig) IsDefined() bool {
+	return c.Filename != ""
+}
+
 func (cfg *Config) Check() error {
 	if err := cfg.Models.Check(); err != nil {
 		return errors.Wrap(err, "config.models")
@@ -138,6 +144,9 @@ func (cfg *Config) Check() error {
 	if err := cfg.Model.Check(); err != nil {
 		return errors.Wrap(err, "config.model")
 	}
+	if err := cfg.Resolver.Check(); err != nil {
+		return errors.Wrap(err, "config.resolver")
+	}
 	return nil
 }
 

codegen/interface_test.go

@@ -3,6 +3,8 @@ package codegen
 import (
 	"testing"
 
+	"syscall"
+
 	"github.com/stretchr/testify/require"
 	"golang.org/x/tools/go/loader"
 )
@@ -41,7 +43,11 @@ func generate(name string, schema string, typemap ...TypeMap) error {
 		SchemaStr: schema,
 		Exec:      PackageConfig{Filename: "tests/gen/" + name + "/exec.go"},
 		Model:     PackageConfig{Filename: "tests/gen/" + name + "/model.go"},
+		Resolver:  PackageConfig{Filename: "tests/gen/" + name + "/resolver.go", Type: "Resolver"},
 	}
+
+	_ = syscall.Unlink(cfg.Resolver.Filename)
+
 	if len(typemap) > 0 {
 		cfg.Models = typemap[0]
 	}

codegen/models_build.go

@@ -8,14 +8,14 @@ import (
 	"golang.org/x/tools/go/loader"
 )
 
-func (cfg *Config) buildModels(types NamedTypes, prog *loader.Program) ([]Model, error) {
+func (cfg *Config) buildModels(types NamedTypes, prog *loader.Program, imports *Imports) ([]Model, error) {
 	var models []Model
 
 	for _, typ := range cfg.schema.Types {
 		var model Model
 		switch typ.Kind {
 		case ast.Object:
-			obj, err := cfg.buildObject(types, typ)
+			obj, err := cfg.buildObject(types, typ, imports)
 			if err != nil {
 				return nil, err
 			}

codegen/object.go

@@ -14,6 +14,7 @@ type Object struct {
 
 	Fields             []Field
 	Satisfies          []string
+	ResolverInterface  *Ref
 	Root               bool
 	DisableConcurrency bool
 	Stream             bool
@@ -77,6 +78,15 @@ func (f *Field) ShortInvocation() string {
 	return fmt.Sprintf("%s().%s(%s)", f.Object.GQLType, shortName, f.CallArgs())
 }
 
+func (f *Field) ResolverType() string {
+	if !f.IsResolver() {
+		return ""
+	}
+	shortName := strings.ToUpper(f.GQLName[:1]) + f.GQLName[1:]
+
+	return fmt.Sprintf("%s().%s(%s)", f.Object.GQLType, shortName, f.CallArgs())
+}
+
 func (f *Field) ShortResolverDeclaration() string {
 	if !f.IsResolver() {
 		return ""